The "operation timed out" response is saying that a request was made from one of our clients to their webserver however their webserver has not responded within a 180 second window.

There are many scenarios that could cause this that mostly have to do with the website host. Have you talked to their host yet?

You can tell them your request to their websites are coming from IP address 192.104.231.235 and ask them if there is anything on their end that would be messing with your http requests to their websites.

For example, lets say they have a load balancer in front of a cluster of servers and that load balancer distributes load based on source IP address. Its possible that any request coming from Lee's public address space gets sent to the same node on their cluster, and perhaps that node has an issue.

Any time you load their website from another public network (such as a local wifi,) it works, right? Because those requests are distributed to other nodes in their cluster that don't have an issue...so what appears to be a Lee problem really isn't. It’s a problem with their end and how they are handling requests from a particular address space.

There are other scenario's too...perhaps they are routing our address space wrong, or they may have an intrusion prevention device denying requests from our address space for either valid or invalid reasons, etc.

We don't block outbound traffic from our network and the fact that our error is saying "operation timed out" to me says the http request was made but there was never a response from their end, for some unknown reason. I think the first thing to do is to reach out to them, give them your public IP address, and see if they come up with anything.